1. Field of the Invention
The present invention relates to a method for managing a defective area on a high density optical disc, and more particularly to a write once optical disc, an apparatus and a method for managing a defective area on a high density optical disc such as a Blu-ray Disc Write Once (BD-WO).
2. Background of the Related Art
A new high density optical disc, on which high quality video, and audio data can be written, erased and rewritten for long periods of time, e.g., a Blu-ray Disc re-writable (BD-RE), is currently being developed.
As seen in FIG. 1, an optical disc device for writing and reproducing data to and from the BD-RE is provided with an optical pickup 11 for writing and reproducing a signal to and from an optical disc 10. A video disc recorder (VDR) system 12 for processing a signal from the optical pickup 11 as a reproduced signal, or demodulating and processing an external data stream into a writable signal suitable for writing is also shown. An encoder 13 for encoding, and providing an external analog signal to the VDR system 12 is also provided in the optical disc device.
As seen in FIG. 2, the BD-RE is divided into, and assigned a lead-in area (LIA), a data area, and a lead-out area (LOA). The data area is provided with a user data area, and an inner spare area (ISA) and an outer spare area (OSA) assigned to a fore end and a rear end of the user data area, respectively. The LIA is provided with a defect management area (DMA) having disc definition structure (DDS) information and a defect list (DFL) information for managing a defective area.
In the meantime, the VDR system 12 of the optical disc device writes the external data in clusters corresponding to an ECC Block unit having a predetermined recording size after encoding and demodulating the external signal into a signal suitable for writing. As shown in FIG. 2, if a defective area is found in the user data area when the data is being written in the user data area, the VDR system 12 carries out a series of replacement writing operations in which the clusters of data written on the defective area are written on one of the spare areas, e.g., on the inner spare area (ISA) in place of the defective area.
The VDR system 12 also writes and manages the defect list information for accessing the data written in the spare area during replacement writing operations. The defect list information has a predetermined recording size, e.g., a fixed recording size of four clusters, and includes a plurality of defect entries (Defect_Entry #1˜#n) each with written location information about the respective defective area, and written location information about the data written in the spare area during replacement.
Therefore, even if there is a defective area in the user data area of the BD-RE, the VDR system 12 can prevent a data writing error in advance by writing the clusters of data written on the defective area on the spare area in place of the detective area, and also reproducing the data from the spare area.
The Blu-ray Disc Write-Once (BD-WO) is another type of high density optical disc that is being developed where a high quality of data can be recorded and reproduced to and from the disc. As the name may suggest, data can be written only once on the BD-WO and is not re-writable on the BD-WO. However, the BD-WO can be read repeatedly. As a result, the BD-WO is useful where the rewritability of data on a recording medium is not desired or essential.
Discussions on the standardization of high density optical discs, e.g., such as BD-WO, have recently been underway. In this regard, a disc structure, a method and an apparatus for managing defective areas of the BD-WO are needed, which accommodate and consider the unique characteristics and intended operations of the BD-WO. Such techniques will render the BD-WO commercially marketable and operationally feasible.